How to stay hydrated during a flight

Why cabin air is so dry

The air introduced into the cabin is drawn from outside at altitudes where natural humidity is almost zero, and the recirculation system does not replenish it for reasons of weight and fuel consumption. The result is an environment with a relative humidity that rarely exceeds 20%, compared to the 40-60% typical of a closed indoor environment on the ground: a factor that accelerates fluid loss through skin and respiratory tract.

How much and how to drink during the flight

The most effective strategy is to drink regularly, small amounts every hour, rather than large amounts sporadically that the body struggles to absorb. Taking a refillable water bottle that you fill after security checks ensures constant access to water without relying solely on the service cart, which on some flights passes only hours apart.

Skin hydration: creams and sprays

Applying a moisturising cream to face and hands during the flight counters the skin dryness that cabin air causes even on the surface, not just internally. A facial hydration spray, used multiple times during a long flight, provides immediate relief and complements the hydration gained from drinking.

Coffee and alcohol: enemies of fluid balance

Coffee and alcoholic drinks are both diuretics and worsen the dehydrating effect already produced by dry air, partially undoing the efforts made by drinking water regularly. In the case of alcohol, recent research indicates an additional effect during sleep on board, with a measurable reduction in blood oxygen saturation: yet another reason to limit it on long flights.

Always take a refillable water bottle to fill after security checks: it is the simplest way to drink regularly without depending on the service cart.